If placement is your highest priority and you’re not getting the main campus because of the marks issues, then Ramapuram Campus is a better option than the NCR campus.
You can stay in the city limits and visit the main campus whenever possible. If you have friends studying in the main campus, you can even go in for a night stay to see the main campus hostel life.
Since the placements would happen in TP Ganesan Auditorium, it is better to reach the campus from the same city than taking your luggage all the way from the North to South.
Hope this helps.
Best wishes! 🙂